Process of preparing 16beta-methyl-11beta-hydroxy steroids



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PROCESS OF PREPARING lofl-METHYL-llfi-HY- DROXY STEROIDS No Drawing.Filed Sept. 3, 1958, Ser. No. 758,697

8 Claims. (Cl. 260-39145) This invention relates to an improved processfor the preparation of l6fl-methyl-11B-hydroxy steroids and is moreparticularly concerned with the production of 3-oXygenated-16fi-methyl-l lfl,l7a,2l-trihydroxy pregnane- 20-ones; 3oxygenated-16/3-methyl-l1B,17a,21-trihydroxy- 4-pregnene-20-ones17a,21-trihydroXy-1,4-pregnadiene-20-ones novel intermediates formed inthis process.

The present process comprises reducing the ll-keto group in a16fi-methyl-17u,2l-dihydroxy-ZO-ketalized steroid of the pregnaneseries, having attached to the carbon in the 3 position either asubstituent containing an unsaturated carbon to nitrogen linkage or aketal substituent, with a metal hydride and hydrolizing the resultinglofi-methyl-l1/3,17u,2l-trihydroxy-20ketalized steroid having attachedto the carbon in the 3 position either a substituent containing anunsaturated carbon to nitrogen linkage or a ketal substituent toreconvert the 3 and the 20 substituents into ketone groups, therebyforming a IGB-methyl-l15-17a,21-trihydroxy-3,20-diketo steroid of thepregnane series, which can be represented by the following structuralformula:

and to the (llHzOH O:

and A and A derivatives thereof.

The present starting compounds, 16 3-methyl-17a-21-dihydroxy-ZO-ketalized steroids, particularly 16,3-rnethyl- 17 20,20 21bisrnethylenedioxy 3 semicarbazido- 4-pregnene-1 l-one165-methyll7-20,20-2l-bismethylenedioXy-3-semicarbazido-1,4-pregnadiene-1l-oneare conveniently prepared by contacting a16/8-methyl-17e,21-dihydroxy-3,20-diketo steroid with formaldehyde inthe presence of an acid to first form the17-20,20-21-bismethylenedioxy-16,B-methyl-3,1l-diketo steroid andsubsequently treating with semicarbazide in a bufiered medium to formthe 17-20,20-2l-bismethylenedioxy-l6 8-methyl-3- semicarbazido-1 l-ketosteroid.

It was previously known to chemists skilled in the steroid art that thell-keto group in a 3-oXygenated-17, 2l-dihydroxy-4-pregnene-11,20-dionecould be reduced by first suitably protecting the 3 and 20-ketonegroupings by formation of the corresponding 3,20-bissemicarbazone,reducing the ll-keto group with an alkali metal borohydride andsubsequently regenerating the 3,20-diketone by hydrolysis with a strongacid, An alternative method, although not a preferable one, was to firstform the 3,20- bisethylenedioxy derivatives of a17,21-dihydroxy-4-pregnene-3,11,20-trione, reduce the ll-keto group insaid bisethylendioxy compound with lithium aluminum hyand3-oXygenated-16fl-methyl-11/3,

dride and subsequently regenerate the 3 and the 20-ketone groupings byhydrolysis with a solution of a strong acid. It has been suggested thatin order to reduce the ll-keto group to a ll/Hiydroxy group in a3-oxygenatedioB-metnyl-l7,21-dihydroxy steroid, first, the3,20-bissernicarbazone of the steroid be formed; second, the Stet-'- oidbissemicarbazone be reduced with sodium borohydride; and third, thedesired product, the 3-oxygenated- 16Brnethyl-l1fi,l7a,21-trihydroxysteroid be formed by treatment of the reduced bissemicarbazone with astrong acid. Unfortunately, this process, when employed in theperparation of an l1fi-hydroxy-16fl-methyl steroid containing also a17oc-hYdr0XYl group, results in extensive elimination of the 17-hydroxylgroup and a consequent poor yield of final product.

It is an object of the present invention to provide a novel process forthe production of 3-oxygenated-1613- methyl-11,3,17a,21-trihydroxysteroids. It is a further object of this invention to provide animproved process for the conversion of the ll-keto group to thellfi-hydroxy group in l6p-methyl-17e-hydroxy steroids and, at the sametime, minimize the dehydration of the l7-hydroxyl group. Another objectis the provision of novel steroid intermediates formed in the operationof this improved process. Another more specific object is the provisionof a novel process for the production of 16pmethylhydrocortisone16,8-methylprednisolone and the 9- halogenated-l6, 3-methylhydrocortisone and prednisolone compounds. For example, treatment of17-20,20-21-bismethylenedioxy 3 semicarbazido 16,8 methyl 4-pregnene-ll-one with a solution of sodium borohydride results in thereduction of the ll-keto group to form 17 20,20 21 bismethylenedioxy1613 methyl 3- semicarbazido-llfi-hydroxyl-pregnene. This compound isthen further treated with a solution of an acid to regenerate the 3 and20-ketone groupings and form 16,3- methyl-llfl,l7a,21-trihydroxy-4-pregnene-3,20-dione.

The starting compounds of the present application are16/8-rnethyl-17a,2l-dihydroxy-ZO-ketalized steroids of the pregnaneseries. These compounds may have, in addition to the 20-ketalsubstituent, an additional protecting group at position 3 of the steroidmolecule. The reagent used for protection of the 3-keto group may beconveniently either a nitrogenous ketone reagent as for example, asemicarbazide, a hydrazine, a hydroxylamine or a substituted alkane diolas for example, ethylene glycol which results in the formation of eithera 3-semicarbazone, a 3- hydrazone, a 3-oxime or a 3-ethylenedioxyderivative. The protection of the 3-ketone group in this manner preventsthe concurrent reduction of the 3-ketone to a 3- hydroxy group. Thus,representative starting materials in our process are16/3-methyl-ll-keto-20-ketalized steroids having attached to the carbonin the 3 position either a substituent containing an unsaturated carbonto nitrogen linkage or a ketal substituent. The preparation of thestarting compounds is shown in detail in preparations 1 through 7.Representative examples of starting materials for our process comprise:

17 20,20 21 bismethylenedioxy 16,8 methyl 3- propylenedioxy-S-pregnene-1l-one 17 20,20 21 bismethylenedioxy 1613 methyl 3- oximino-4-pregnene-1l-one 17 20,20 21 bismethylenedioxy 16 8 methyl 3-phenylhydrazino-4-pregnene-1 l-one 17 20,20 21 bismethylenedioxy 16 3methyl 3- propylenedioxy-pregnane-1 l-one 17 20,20 21 bismethylenedioxy1619 methyl 3- oximino-pregnane-l l-one 17. 20,20 21 bismethylenedioxy16B methyl 3- phenylhydrazino-pregnane-1 l-one 17 20,20 21bismethylenedioxy 16 3 methyl 3- oximino-l ,4-pregnadiene-1 l-oneRegarded in certain of its broader aspects, the present inventioncomprises reducing the ll-keto substituent in a 163-methyl-17a,21-dihydroxy ZO-ketalized steroid of the pregnane series,having attached to the carbon in position three of the molecule either aketal substituent or a substituent containing an unsaturated carbon tonitrogen linkage, to, form the corresponding 16fi-methyl-11/3- hydroxycompound and hydrolyzing the 3 and 20 substituents of said llfl-hydroxycompound with a solution of an acid to form a16fl-methyl-11B,17a,21trihydroxy- 3,,20-diketo steroid of the pregnaneseries.

In carrying out the first stepof our novel process, the,lop-methyl-17a,21-dihydroxy 20 ketalized steroid having an additionalprotecting group at the 3 position is treated with a solution or asuspension of a metal hydride reducing agent to produce a novel16f3-methyl- 11,8,17a,21-trihydroxy-20-ketalized steroid. Thus, forexample, 16fi-methyl-17-20,20-21 bismethylenedioxy 3-semicarbazidot-pregnene-1l-one; 16,8 methyl 17-20,ZO-ZL-bismethylenedioxy 3 semicarbazido- 1,4-pregnadiene 11 one;l6,8-methyl-17-20,20-2l-bismethylenedioxy 3 semicarbazidopregnane-ll-one; 16fi-methyl- 17-20,20-21 bismethylenedioxy 3ethylenedioxy 5- pregnene 11 one;16fi-methyl-17-20,20-2l-bismethylenedioxy 3-ethylenedioxy pregnane-ll-one; 165-methyl- 3,20 bisethylenedioxy-l7a,2l dihydroxy-S-pregnene-l1- one and 16d methyl-3,ZO-bisethylene-dioxy-17a,21-dihydroxy pregnane11 one are converted by this reduction treatment to the novelllfl-hydroxy steroids as, for example, 163 methyl17-20,20-21-bismethylenedioxy- 3 -semicarbazido 11;; hydroxy-4-pregnene;16fl-methyl- 17-20, 20-2 1 bismethylenedioxy 3 semicarbazido-llfihydroxy1,4 pregnadiene; 16,8-methyl-17-20,20-21bismethylenedioxy3-semicarbazido-1lfl-hydroxy pregnane; 163 methyl17-20,20-2l-bismethylenedioxy 3- ethylenedioxy-llfi-hydroxy 5 pregnene;165 methyl 17-20, 2 -21-bismethylenedioxy 3 ethylenedioxy pregnane, 16Bmethyl 3,20-bisethylenedioxy 1lfl,17a,21-trihydroxy 5. -pregnene and16p-methyl-3,20-bisethylenedioxy 11,6,17ot,2l trihydroxy pregnane. Theprocess is carried out by mixing a suitably protected 16B-methyl-11-keto steroid, using either order of addition, with at least atheoretical amount of metal hydride reducing agent such as, for example,lithium aluminum hydride, sodium borohydride, or lithium borohydride inan organic solvent which is non-reactive under the reaction conditions,at a temperature below about 120 C. preferably between about 25 C. and100 C. Usually, it is preferred to use an excess of reducing agent,preferably between about and 20 moles of reducing agent per mole of thestarting 16B-methyl-1l-keto steroid. The time required for the reactionis not critical and may be varied between about one hour and up to about24 hours. The length of time is dependent, of course, on the solvent,the temperature, and the particular reducing agent employed. The excessnon-reacted reducing agent is then hydrolyzed in tlie ordinary manner,preferably by the addition of an ice and Water mixture, or a solution ofa dilute acid and the 1-6fi-methyl-11,B-hydroxy steroid separated fromthe reaction mixture by conventional methods, such as filtrationorextraction. The solvent used is preferably one which is non-reactiveunder the reaction conditions, and

for this purpose there are a number which are suitable such as, forexample, ether, benzene, tetrahydrofuran, dioxan, a lower alcohol, andthe like.

In a preferred embodiment of this reduction process a solution of16B-methyl 17-20,20-2l-bismethylenedioxy-3-semicarbazido-1,4-pregnadiene 11-one in tetrahydrofuran is contactedwith a solution of an excess of sodium borohydride dissolved in aqueoustetrahydrofuran. The mixture is then stirred at the reflux temperaturefor a period of about 18 hours. Additional sodium borohydride is thenadded to the mixture and the reaction mixture heated again for another 7hours to insure complete reduction of the ll-keto group. Following thisadditional 7-hour treatment, the reaction mixture is cooled, the excessreducing agent hydrolyzed by treatment with a mixture of aqueous aceticacid and the volatile solvents removed from the product by evaporationof the reaction mixture, in vacuo. The product is then precipitated bythe addition of a small amount of Water to the residual material and theresulting aqueous slurry filtered to recover the product,16B-methyl-17-20,20-2l-bismethylenedioxy-3-semicarbazido-1,4-pregnadiene-11 [3-01,

When the starting ll-keto steroid compound contains as one of itsprotective substituents an unsaturated carbon to nitrogen linkageattached to the three, position, of the molecule, it is preferred touse, as. the reducing agent, an alkali metal borohydride since lithiumaluminum hydride is thought to affect substantial reduction of anunsaturated carbon to nitrogen linkage as, for example,

a semicarbazone, an oxime, or an arylhydrazone. How ever, when both the3 and 20 positions are protected by ketal substituents, any of thewell-known metal hydride reducing agents may be employed as mentionedabove,

as for example, an alkali metal borohydride or an alkali metal aluminumhydride, and the like.

In carrying out the novel hydrolysis step, the second step in the abovedescribed procedure, the novel 16;?- methyl-llfl-hydroxy steroid havingboth they 3 and 20 positions protected obtained by the above reduction;

process, is dissolved in an organic solvent which may be non-reactiveunder the conditions of reaction such as, for example, methanol,acetone. isopropyl alcohol, methyl ethyl ketone, benzene, and the like,or mixtures of the above solvents. Alternatively, the, solvent for thesteroid may be one which itself eifects the hydrolysis reaction as, forexample, an aqueous solution of acetic or formic acids. The acidhydrolyzing agents ordinarily employed are the mineral acids such as,for example, hydrochloric acid, sulfuric acid, phosphoric acid or, asmentioned above, a strong lower aliphatic carboxylic acid, such asacetic or formic acid, and the like aqueous acetic acid being preferred.The concentration of the hydrolyzing agent is not critical, andsolutions having a pH of abovetwo up to solutions concentrated withrespect to the acid are acceptable, the range, in the case of mineralacids, from about 0.1 normal to 2 normal being preferred, and in thecase of the lower aliphatic carboxylic acids, approximately 21 10aqueous solution of the acid being preferred. The order of addition ofreactants is not critical and any order of admixture with the startingsteroid, hydrolyzing agent, and/or water is satisfactory.

The reaction is conducted at temperatures ranging between about 0 C. andthe boiling point of the reaction mixture, temperatures at or near theboiling point of the mixture ordinarily being preferred. In actualpractice the llfi-hydroxy steroid is dissolved in the solvent, with orwithout additional hydrolyzing agent, and the mixturemaintained slightlybelow the boiling point for a period of approximately 4 hours whenaqueous acetic acid is used as the solvent and the hydrolyzing agent.

When hydrolysis of the llfi-hydroxy steroid is substantially complete,the volatile solvents are removed in conventional manner, preferably byevaporation of the total mixture in vacuo, to yield a residue containingthe desired 16p-rnethyl-11B,17u,21-trihydroxy 3,20- diketor Thefollowing examples are given for purposes of illustration and not by wayof limitation:

PREPARATION 1 1 7-20,.20-21-bismethylenedi0xy-1(SB-methyl-4-pregnene-3,I1 -dine To a stirred solution of 7.43 g. of165-methyl-17a,21- dihydroxy 4 pregnene 3,11,20 trione in 365 ml. ofmethylenechloride at room temperature is added a solution, premixed at 0C., of 110 ml. of low methanol content formaldehyde (37% aqueoussolution) and 110 ml. of concentrated hydrochloric acid. The reactionmixture is stirred at room temperature (approximately 25 C.) and 960 ml.of water are added. The layers are separated and the aqueous layer isextracted with three 200 ml. portions of methylene chloride. Thecombined methylene chloride extracts of the product are washedsuccessively with 200 ml. of water, aqueous potassium bicarbonatesolution, and again with a 200 ml. portion of water. The methylenechloride solutions are then dried over magnesium sulfate and evaporatedto dryness in vacuo to form a residue comprising the product. Ontritnration of the residue with ether substantially pure product isobtained, M.P. 236-247 C. dec.

AEZQH 2380, E% 367 gllixcls 6.00, 6.15, 9.1-9.2 n

PREPARATION 2 1 711-2 0,2 0-2 1 -bismethylenedi0xy-1 6/3-methy l-1,4-pregnadiene-3,1Z-dione To a stirred solution of 1.15 g.l7u,21-dihydroxy-16flmethyl lA-pregnadiene-ll1,20-trione and 60 ml. ofmethylene chloride is added a cold (05 C.) premixed solution of 17 ml.of 37% aqueous formaldehyde (low methanol) and 17 ml. of concentratedhydrochloric acid. The mixture is stirred vigorously for 40 hours at 25C., approximately 120 ml. of Water is added and the mixture extractedthree times with methylene chloride. The combined methylene chlorideextracts containing the product are washed successively with excessaqueous potassium bicarbonate solution and with Water, then dried overmagnesium sulfate and evaporated to dryness in vacuo to yield a residuecomprising the product. Crystalline17u-20,20-21-bismethylenedioxy-16B-methyl- 1,4-pregnadiene-3,1l-dione isobtained by crystallization from acetone ether. M.P. 203-206;

OHO x 5.84, 6.00, 6.13, 6.19, 9.15,

PREPARATION 3 3-semicarbazz'do-1 7u-20,20-21-bismethylenedioxy-16B-methyl-1,4-pregnadiene-1I-one .0 295 mu E% 4 246 mu E% 219 maxPREPARATION 4 3-semicarbazid0J 711-2 0,2 0-21 -bismethylenedioxyl 6{3-methyl-4-pregnene-1 1 -one To a solution of 200 mg. of 17a-20,20-21-bismethy1- enedioxy--methyl-4-pregnene-3,ll-dione in 5 ml. ofmethanol and 2.5 ml. of dimethyforrnamide is added 160 bg. ofsemicarbazide free base and 40 mg. of semicarbazide hydrochloride. Themixture is stirred at 25 C. for 18 hours during which time the productpartially precipitates. Water is then added and the product filtered,washed in water and dried in air to give3-semicarbazido-17a,20,20-21-bismethylenedioxy 16,8 methyl- 4-pregnene-1l-one.

PREPARATION 517a-20,20-21-bismethylenedioxy-Mfi-methylpregnane-3,1I-di0ne To astirred solution of 3.3 g. of 17a,2l-dihydroxy-16fl-methylpregnane-3,l1,20-trione dissolved in 120 m1. of methylenechloride is added a cold premixed solution of 34 ml. of 37% aqueousformaldehyde (low methanol) and 34 ml. of concentrated hydrochloricacid. The mixture is stirred vigorously for 30 hours at 25 C. to formthe product. To the mixture is added approximately 250 ml. of water andthe two phase system is then extracted three times with methylenechloride to extract the product. The combined methylene chloride extractis then washed successively with excess 5% aqueous potassium bicarbonatesolution and water and the washed extract is dried over magnesiumsulfate. The methylene chloride is removed by evaporation in vacuoleaving a solid residue comprising the product. This residual solid iscrystallized from a mixture of acetone and ether to give substantiallypure 17a-20,20-2l-bismethylenedioxy-lfifimethylpregnane-3, 1 l-dione.

PREPARATION 6 3,2 O-b isethy lenedioxy-I 6 fi-methyl-I 7oc-21dihydroxy-S -pregnene-1 1 -one To a solution of 500 mg. of16B-methyl-17a,2l-dihydroxy-4-pregnene-3,11,20-trione in 10 ml. ofethylene glycol and 50 ml. of benzene is added 50 mg. of p-toluenesulfonic acid monohydrate and the mixture is refluxed for 20 hoursutilizing a Water separator to remove the water as it azeotropicallydistills. The mixture is then cooled to room temperature and 0.1 g.potassium hydroxide in 2 ml. of ethanol was added. .An equivalent amountof water is added to the mixture and the organic layer containing theproduct is separated, dried and the solvent removed by concentration invacuo to yield a residue comprising the product. The residue is thencrystallized from a mixture of acetone-ether to give substantially pure3,20-bisethylenedioxy-;.2l-dihydroxy- 5-pregnene-ll-one. The productgives a negative tetrazolium test and exhibits no maxima above 220 mu inthe ultraviolet region.

PREPARATION 7 3-ethylenedioxy-1 7a-20,20-21 -bismethylenedi0xy- 16,8-methyl-5-pregnene-11-one arated, dried over sodium carbonate andconcentrated in vacuo to yield a solid residue comprising the product.The solid residue is then crystallized from a mixture of acetone andether to give substantially pure3-ethylenedioxy-17a-20,20-21-bismethylenedioxy 4 pregnene-l 1- one. Thismaterial shows a negative tctrazolium test and exhibits no maxima above220 mu in the ultraviolet absorption region.

The starting compounds of the present application are prepared from new16fl-methyl steroids which are prepared in accordance with proceduresdescribed in the copending application of David Taub, Norman L. Wendler,and Harry L. Slates, Serial No. 722,390, filed March 19, 1958. Theseprocesses are as follows:

To a solution of 3a-acetoxy-l6-pregnene-l1,20-dione in a mixture oftetrahydrofuran and ethyl ether is added diazomethane to produce3a-acet0xy-l6a,Not-methyleneazopregnane-l1,20-dione (M.P. 186l90 C.)which precipitated from solution. Heating this compound at about 180 C.in vacuo produces 3a-acetoxy-16-methyl- 16-pregnene, 11,20, dione (MP.165167 C.) which upon reaction with hydrogen peroxide in the presence ofsodium hydroxide in methanol solution for 18 hours at room temperatureaflords 16a,l7a-epoxy-3a-hydroxy- 16/3-methyl-pregnane-11,20-di0ne (M.P.l78-180 C.). When this compound is treated with perchloric acid inaqueous dioxane at 25-30" C. for 65 hours and the resulting reactionmixture is diluted with water a mixture of 3a,17a-dihydroxy-l6-methyl-15-pregnene-11,20-dione and3a,17a-dihydroxy-16-methylene-pregnane (M.P. 158--167' C.) isprecipitated and recovered by filtration. Reduction of this mixture withhydrogen in methanol in the presence of palladium-calcium carbonatecatalyst affords a mixture of 30L,17OL-dlhydIOXy-160t-Il'l6thy1-pregnane-11,20-dione and 3a,17a-dihydroxy-16fi-methy1-pregnane-11,20-dione sintering at 150 C. Bromination of this mixturewith bromine in chloroform at 40-45 C. affords a mixture of21-bromo-3a,17a-dihydroxy-16amethylpregnane-l1,20-dione and21-bromo-3a,17a-dihydroxy-16B-methylpregnane-11,20-dione which uponreaction with potassium acetate and potassium iodide in acetone producesa mixture of 3a,17o,2l-trihydroxy-165-methyl-pregnane-l1,20-dione-2l-acetate and 3a,17a,21trihydroxy-16a-methylpregnane-11,20-dione-21 acetate.

To a solution. of the above mentioned mixture of 21-acetates in aqueoust-butanol at 10-15 C. is added N-brornosuccinirnide to produce a mixtureof l7a,21- dihydroxy 16cc methylpregnane 3,11,20 trione 21- acetate and1711,21-dihydroxy-16fi-methylpregnane-3,11, 20-trione-21-acetate whichon chromatography on neutral aumina and elution with chloroform-benzene(1:1) and benzene yield 17ot,21-dihydroxy-16fi-methylpregnane-3,11,20-trione-21-acetate (M.P. 210213 C.). The 17a, 21 dihydroxy 16Bmethylpregnane-3,11,20-trione-21- acetate thus obtained is then reactedwith potassium bicarbonate and aqueous methanol to produce the 21-alcohol. Reaction of this compound with bromine in a mixture of aceticacid and chloroform affords the corresponding 4-bromo compound (M.P.165170 C. dec.) which is converted by reaction with semicarbazide to the3-semicarbazone of 17u,21 dihydroxy 165 methyl-4-pregnene-3,11,20-trione-21-acetate. Treatment of this compound with amixture of acetic acid and pyruvic acid gives 170.,21dihydroxy-16B-methyl-4-pregnene-3,11,20- trione-21-acetate (M.P. 226-232C.). This compound is converted to the corresponding 1,4-pregnadienecompound by reacting it with selenium dioxide in t-butyl alcohol underreflux for 48 hours. The 17u,21-dihydroxy 165 methyl-1,4-pregnadiene-3,11,20-trione-21- acetate so obtained is then reactedWith potassium bicarbonate in aqueous methanol to produce the21-alcohol. Thus 17a,21'-dihydroxy 165 methyl-4-pregnene-3,11,20-trione-21-acetate obtained above is similarly reactedwithpotassiumbicarbonate in aqueous methanol to;pro.duce. .the' 21.-alcohol.

8 PREPARATION s 1 6 3-m ethyl-1 7-20,20-21 -bismethy lenedioxy-3'-ethylenedioxy pregnane-II -one To a solution of 250 mg. of16fi-methyl-17-20,20-21- bismethylenedioxy pregnane-3,11-dione, whichmay be prepared as described in Preparation 5, in 10 ml. of ethyleneglycol and 30 ml. of benzene is added 25 mg. of p-toluene sulfonic acidmonohydrate and the mixture refluxed for a period of approximately 15hours using a water separator to remove the water as it azeotropicallydistills. The entire reaction mixture is then cooled to room temperatureapproximately 25 C.) and 0.1 g. potassium hydroxide and 2 ml. of ethanolis added. Approximately 15 ml. of water is added to the mixture and theorganic layer containing the product is separated, dried and. thesolvent removed by concentration in vacuo to yield a residue comprisingthe product. The product is then crystallized from a mixture ofacetoneether to give substantially pure 16/i-methyl-l7-20,20-21-bismethylenedioxy 3 ethylenedioxy pregnane-ll-one. This materialexhibits a negative tetrazolium test and shows no maxima above 220 mu inthe ultraviolet region.

PREPARATION 9 1 6 fl-methy l-J 7-20,20-21-bismethylenedioxy-3-semicarbazid0 pregnane-J 1 -one To a solution of mg. of17-20,20-21-bismethylenedioxy-l6,6-methyl-pregnane-3,1l-dione in 3 ml.of methanol and 1.8 ml. of dimethylformamide is added 120 mg. ofsemicarbazide free base and 40 mg. semicarbazide hydrochloride. Thereaction mixture thus formed is stir-red at 25 C. for about 20 hours,during which time the product partially precipitates. Water is thenadded to completely precipitate the product and the product is recoveredby filtration. It is then washed with water on the filter and air driedto give crystalline methyl 17-20,20-21 bismethylenedioxy-3semi carbazidopregnane-l l-one.

PREPARATION 10 16B-methyl-17a,21 -dihydroxy-3,20-bisethylenedioxypregnane-I 1 -one Approximately 400 mg. of 16fi-methyl-l7a,21dihy droxypregnane-3,11,20-trione is dissolved in approximately 10 ml. ofethyleneglycol and 40 ml. of benzene. To the mixture is added 40 mg. ofp-toluene sulfuric acid monohydrate and the reaction mixture maintainedfor a period of about 24 hours at reflux temperature utilizing a waterseparator to remove the water as it azeotropically distills. The mixtureis then cooled to room temperature and 0.1 g. potassium hydroxide and 2ml. of ethanol is added. An equivalent amount of water was added to themixture and'the organic layer containing the product is separated, driedand the solvent removed by concentration in vacuo to yield a residuecomprising the product. This residual material is then crystallized froma mixture of acetone-ether to give substantially pure16/3-methyl-3,ZO-bisethylenedioxy-17a, 21-dihydroxy pregnane-ll-one.

EXAMPLE 1 16,8-methyl-1 1 ,8,1 70;,21 -trihydroxy-1,4-pregnadiene-3,20-dione A. Reduction step:

A solution is prepared by dissolving 2.10 mg. of 165-methyl-17-20,20-2l-bismethylenedioxy 3-sernicarbazido--1,4-pregnadiene-11-one in 10 ml. of tetrahydrofuran. To the solution isadded 300 mg. sodium borohydride in 1 ml. of water and 1 ml. oftetrahydrofuran. The mixtureis stirred while maintaining it at thereflux temperature for approximately 18 hours. Additional sodiumborohydride (approximately 200 mg.) is then added to insure completereduction of the ll-keto function, and the mixture stirred andmaintainedat the reflux temperature for product is filtered, washed withwater and dried in air to give substantially pure16,8-rnethyl-l7-20,20-2l-bismethylenedioxy-3-semicarbazido-1,4-pregnadiene-l1,3-01

xCHHOH 294., 245 mu B. Hydrolysis step:

Approximately 210 mg. of the product formed in part A of this example isdissolved in 15 ml. of acetic acid and 15 ml. of water and thetemperature of the mixture is 'maintained at about 100 C. by Warming onthe steam bath for about 4 hours. The entire mixture is then cooled toroom temperature and concentrated in vacuo nearly to dryness. A solutionof aqueous sodium chloride is then added to the residual materialcontaining the product, and the product is extracted with ethyl acetate.The separated ethyl acetate extract of the product is washedsuccessively with 5% aqueous potassium bicarbonate solution and aqueoussodium chloride solution, dried over magnesium sulfate, and afterremoval of the drying agent by filtration the filtrate containing theproduct is concentrated to a solid residue.16,8-methyl-1l5,17a,2l-trihydroxy-l,4-pregnadiene-3,20-dione iscrystallized by trituration of the residue in ether and can be furtherpurified by crystallization from a mixture of acetone-ether, M.P.205210;

igg 243 mu E% 381 x3; 2.90, 3.00, 5.85, 6.02, 6.16, 6.21, 11.24

EXAMPLE 2 16B-methyl-11fi,17a,21-trihydroxy-4-pregnene-3,20dione A.Reduction step:

' To a solution of 500 mg. of 16fi-methyl-17-20,20-21-bismethylenedioxy-3-semicarbazido-4-pregnene 11 one, which may beprepared as described in Preparation 4 above, in 25 ml. oftetrahydrofuran is added 750 mg. of sodium borohydride and 2.5 ml. ofwater and 2.5 ml. of tetrahydrofuran. The mixture is stirred whilemaintaining it at the reflux temperature for a period of about 15 hours.Another 300 mg. of sodium borohydride is added and the mixture stirredand refluxed for an additional 5 hours. It is then cooled, 2.2 ml. ofacetic acid and 5 ml. of water is added and the major portion of thesolvent is removed by concentration of the mixture in vacuo. Water isthen added to precipitate the formed product and the precipitate isfiltered, washed with water and dried in air to give16fi-methyl-17-20,20-2l-bismethylenedioxy-3-semicarbazido-4-pregnene-l1,8-01.

B. Hydrolysis step:

A solution of 420 mg. of 17-20,20-2l-bismethylenedioxy-3-semicarbazido-4-pregnene-l118-01 (prepared as described in part A ofthis example) and 30 ml. of acetic acid and 30 ml. of Water is preparedand heated to approximately 100 C. on the steam bath for a period ofabout 4 hours. The entire reaction mixture is then cooled andconcentrated in vacuo nearly to dryness. To the residualmaterialcontaining the product is added aqueous sodium chloride solutionand the slurry which forms is extracted with ethyl acetate to remove theproduct. The organic extract, containing the product, is successivelywashed with 5% aqueous potassium bircarbonate solution and aqueoussodium chloride solution, dried and concentrated to dryness to yield aresidue comprising the product. Substantially. pure 1613-methy1-11p,l7a,21-trihydroxy-4-pregnene-3,20-dione is then obtainedby trituration with ether. The product may be further purified bycrystallization from a mixture of acetone-ether.

EXAMPLE 3 16fi-methyl-I1/3J 70;,21-trihydroxy-4-pregnene-3,20-dione A.Reduction step:

To mg. of 16p-methyl-3,20-bisethylenedioxy-l7a,21-dihydroxy-5-pregnene-1l-one (prepared as described in Preparation 6above) in 10 ml. of dried tetrahydrofuran is added 100 mg. of lithiumaluminum hydride and 5 ml. of tetrahydrofuran. The mixture is maintainedat its reflux temperature in an atmosphere of nitrogen for about 1 /2hours. The entire reaction mixture is then cooled to about 25 C. and 1ml. of ethyl acetate added to the mixture to destroy any excess lithiumaluminum hydride present. Approximately 1 ml. of saturated solution ofsodium sulfate is then added to the mixture to eifect precipitation ofany inorganic salts present, following which approximately 2 g. ofanhydrous magnesium sulfate is added to remove any water present in themixture. The inorganic precipitate is then removed from the reactionmixture by filtration and the precipitated inorganic salts washed on thefilter with a small amount of ethylacetate to wash out any occludedproduct. The filtrate and washings containing the product are combinedand evaporated. to dryness in vacuo to give a solid residue comprisingIGB-methyl-IIB, 17a,21-trihydroxy-3,20-bisethylenedioxy-5-pregnene.

B. Hydrolysis step:

The product obtained according to part A of this example is dissolved in10 ml. of methanol and to the solution is added 10 ml. of 4 N sulfuricacid solution. The resulting solution is refluxed for about an hour,then is cooled and neutralized with about 10 ml. of dilute sodiumbicarbonate solution. At first, a precipitate of inorganic salts formson addition of the bicarbonate solution. The mixture is concentrated ona steam bath under reduced pressure, whereupon the inorganic saltsdissolve and the organic product begins to precipitate. After most ofthe product precipitates the mixture is cooled to effect more completeprecipitation and filtered to recover the product, 16B-methyl-115,17a,21-trihydroxy-4-pregnene-3 ,ZO-dione.

EXAMPLE 4 16/3-methyl-11flJ70:,21-trihydr0xy-4-pregnene-3,20-di0ne A.Reduction step:

To a suspension of mg. of lithium aluminum hydride and 5 ml. ofanhydrous ether is added 350 mg. ofl6fl-methyl-l7-20,20-2l-bismethylenedioxy-3ethylenedioxy-S -pregnene-1l-one dissolved in 20 ml. of tetrahydrofuran. The material is addedslowly while constantly cooling the reaction mixture. After all thesteroid solution has been added, the mixture is heated at refluxtemperature for approximately 2% hours and is then cooled and the excessreducing agent is decomposed by the cautious addition of water. To thereaction mixture is then added approximately 4 ml. of water followed by20 ml. of ether. The precipitate which forms is removed by filtration.To the filtrate containing the product is added 20 ml. of water and theether layer containing the product is separated. The ether extract isthen Washed with water and concentrated to dryness yielding a cruderesidue com prising 168-methyl-l7-20,20-2I-bismethyIenedioxY-S-ethylenedioxy-S-pregnene-l13-01.

B. Hydrolysis step:

The product obtained according to part A of this example is dissolvedwithout further purification in 20 ml. of acetic acid and 20 ml. ofwater and the mixture is warmed on a steam bath (approximately 100 C.)for about 5 hours. It is then cooled and concentrated nearly to drynessin vacuo. Aqueous sodium chloride is added to the nearly dried residuecontaining the product and the aqueous mixture extracted with ethylacetate. The ethyl acetate extract is washed with 5% aqueous potassiumcarbonate solution and aqueous sodium chloride solution, dried overanhydrous magnesium sulfate, and the dried organic extract concentratedto dryness to give a residue comprising16fi-methyl-l118,170,21-trihydroxy-4-pregnene- 3,20-dione.

EXAMPLE 16fi-me'thy l-] 1,6,] 7a,21-trihydroxy pregnane-3 ,2 O-dione A.I Reduction step: I

A solution of 200 mg. of16B-methyl-17-20,20-2l-bismethylenedioxy-3-ethylenedioxy pregnane-ll-oneand 100 mg. of lithium borohydride in 4 m1. of tetrahydrofuran isallowed to reflux for a period of approximately 1.5 hours. Two ml. of2normal sulfuric acid is then carefully added in order to destroy theexcess reducing agent. The reaction mixture is then cooled, poured intoa mixture of ice and water, and extracted several times with ethylacetate. The ethyl acetate solution is washed with water and dried overanhydrous sodium sulfate. After removal of the drying agent byfiltration, the filtrate containing the product is evaporated to drynessto give 16,8-methyll7-20,20-21-bismethylenedioxy-3-ethylenedioxypregnanc- 1113-01.

B. Hydrolysis step:

The product obtained in part A of this example is dissolved in ml. ofacetic acid and 15 ml. of water. The resulting solution is heated toabout 100 for a period of about 6 hours. It is then cooled andconcentrated in vacuo nearly to dryness. The product is extracted withethyl acetate and the combined ethyl acetate extract is washedsuccessively with aqueous 5% potassium bicarbonate solution and aqueoussodium chloride. The separated extracts are then dried over magnesiumsulfate. After removal of'the drying agent by filtration the filtratecontaining the product is concentrated to drynessto yield a residuecomprising as the principal organic product,16fl-methyl-11/3,17a,2l-trihydroxy pregnane-3,20-dione.

EXAMPLE 6 1'6B-methyl-115J 7a,21 -trihydroxy pregnane-j,20 dione A.Reduction step:

To a solution of 300 mg. of 16fi-methyl-17-20,20-21-bism'ethylenedioxy-3-ethylenedioxy pregnane-ll-one in 15 ml. oftetrahydrofuran is added 400 mg. of sodium borohydride in 2 ml. of waterand 2 ml. of tetrahydrofuran. The mixture is stirred and refluxed forabout 15 hours; At this point approximately 200 mg. additional sodiumborohydride isadded and the mixture is stirred and refluxed anadditional 6 hours. The entire reaction mixture is then cooled, 1 m1.acetic acid in 2 ml. of water was added in order to destroy the excessreducing agent and most of the solvent removed by concentration of thereaction mixture in vacuo. Additional water is added to effect-completeprecipitation of the product, 16fl-methyl-17-20,20-21-bismethylenedioxy-3-semicarbazido pregnanc- 11 [3-01, andthe precipitate filtered, washed with water and dried in air.

B. Hydrolysis step:

The product obtained in part A of this example is dissolved in 20ml. ofacetic acid and 20 ml. of water and the mixture maintained at about 100C. for a period of about 6 hours. The reaction mixture is then cooled toroom temperature and concentrated nearly to dryness. The formed productis extracted from: the reaction mixture, after first adding aqueoussodium chloride solution, with several portions of. ethyl acetate. Theethyl acetate extract containing the product is washed with aqueouspotassium carbonate "solution and aqueous sodium chlorid'e'solution,drieda'nd concentrated to dryness. The residual materialreadilycrystallizes on trituration with ether to give substantiallypur eISp-methyl-l 1,8,17a,2'1- trih'ydroxy pregnane-3,20-dionet 12 EXAMPLE 716/3-methyl-I1/3J7a,21-trihydr0xy pregnane-3,20-dione In the mannerdescribed in Example 3, 17a,21-dihydIoxy-3,ZO-bisethylenedioxypregnane-ll-one is refluxed with lithium aluminum hydride in solutionwith tetrahydrofuran and then hydrolyzed with aqueous sulfuric acid toyield 16B-methyl-l1fl,17a,21-trihydroxy pregnanc- 3,20-dione.

Various changes and modifications may be made in the present invention,certain preferred embodiments of which are herein disclosed, withoutdeparting from the scope thereof; to the extent that these changes andmodifications are within the scope of the appended claims, they are tobe considered a part of this invention.

We claim: 7

1. A process for the preparation of a member of the group consisting ofthe IGB-methyl-l1,13,l7a,21-tl'ihydroxy-ZO-keto steroid of the formula;

CHBOH and A and A derivatives thereof which comprises contacting acorresponding 16fl-methyl-17a,2l-dihydroxy-ZO- ketalized-ll-keto steroidhaving attached to the carbon in the three position a substituentcontaining an unsaturated carbon to nitrogen linkage selected from thegroup consisting of semicarbazones,hydrazones and oximes with a metalhydride reducing agent to form the corresponding lfip-m ethyl-llfl,l7a,21-trihydroxy-20-ketalized steroid having attached to the carbonin the three position a substituent containing an unsaturated carbon tonitrogen linkage and contacting said 1 1fi-hydroxy-20-ke'tali zedsteroidiwitha solution of an acid. 7 V

2. A process for the preparation of a member the group consisting of thel6B-methyl-l1B,17a,2l trihydroxy ZO-keto steroid of the formula;

and A and A derivatives thereof, which comprises con tacting acorresponding 16 3-methyl-l7-20,20 2 1 bisnieth yle'nedioxy11-ketosteroid, having attached to the Car bon in the three position asubstituent containing aiiuii saturated carbon to nitrogen linkageselected fro nitiie group consisting of semicarbazones, hydraz'ones" andoximes, with an. alkali metal borohydride to form the corresponding16,8-methyl-11/3-hydr0xy-17-20,20 2l bismethylenedioxy steroid havingattached to the carbon in the three position a substituent containing anunsaturated carbon to nitrogen linkage and contacting said" H B-T13"droxy steroid with a solution of an acid:

3: A process for thepreparation of a member of the group consisting ofthe 16/3-methy1-11,8,17a,21-trihydroxy-ZO-keto steroid of the formula;

onion and A and A derivatives thereof, which comprises contacting acorresponding16;3-methyl-17-20,20-21-bisrnethylenedioxy-3-semicarbazido-1l-ketosteroid with an alkali metal borohydride to form the corresponding16p-methyl- 17-20,20-21-bismethylenedioxy-3-semicarbazido 1113 hydroxysteroid and contacting said 3-semicarbazido-11/3- hydroxy steroid with asolution of an acid.

4. A process for the preparation of 16,8-methyl-11B,170:,2l-trihydroXy-4-pregnene 3,20 dione, which comprises contacting16/8-methyl-17-20,20-2l-bismethylenedioxy-S-semicarbazido-4-pregnene-1l-onewith sodium borohydride to form 16,3-methyl-l1,6-hydroxy-17-20,20-21-bismethylenedioxy-3-semicarbazido 4 pregnene and contacting saidllfi-hydroxy-4-pregnene with a solution of aqueous acetic acid.

5. A process for the preparation of 16p-methy1-11B, 17a,21-trihydroxy1,4 pregnadiene 3,20 dione, which 14 comprises contacting16,B-methyl-17-20,.20-21-bismethylenedioxy-3-semicarbazido-1,4-pregnadiene-1l-one with sodium borohydride to form l6/8-methyl-11p-hydroxy-17-20,20-21-bismethylenedioxy-3-semicarbazido-1,4-pregnadiene andcontacting said 1lfl-hydroxy-1.,4-pregnadiene with a solution of anacid.

6. A process for the preparation of lofl-methyl-llfl, 17a,21-trihydroxypregnane-3,20-dione, which comprises contacting16,8-methyl-17-20,20-2l-bismethylenedioxy-B- semicarbazido pregnane-ll-one with sodium borohydride to form l68-methyl-l1,B-hydroxy-17-20,20-21-bismethylenedioXy-3-semicarbazid0pregnane and contacting said llfi-hydroxy pregnane with a solution of anacid.

7. A process for the preparation of 1613-methyl-1 1 B,17a,2l-trihydroxy-4-pregnene-3,ZO-dione, which comprises contacting16fi-methyl-17-20,2O 21-bismethy1enedioXy-3-semicarbazidol-pregnene-1lfl-ol with a solution of an acid.

References Cited in the file of this patent UNITED STATES PATENTS HerzogSept. 30, 1958 Beyler et a1 Dec. 30, 1958

1. A PROCESS FOR THE PREPARATION OF A MEMBER OF THE GROUP CONSISTING OFTHE 16B-METHYL-11B,17A,21-TRIHYDROXY-20-KETO STEROID OF THE FORMULA,